package com.premize.grco.dataaccess.sessionFactory;

import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.cfg.Configuration;


/**
 * Configures and provides access to Hibernate sessions, tied to the
 * current thread of execution.  Follows the Thread Local Session
 * pattern, see {@link http://hibernate.org/42.html }.
 *
 * @author Zathura Code Generator http://code.google.com/p/zathura
 */
public class HibernateSessionFactory {
    /**
     * Location of hibernate.cfg.xml file.
     * Location should be on the classpath as Hibernate uses
     * #resourceAsStream style lookup for its configuration file.
     * The default classpath location of the hibernate config file is
     * in the default package. Use #setConfigFile() to update
     * the location of the configuration file for the current session.
     */
    private static String CONFIG_FILE_LOCATION = "/hibernate.cfg.xml";
    private static final ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();
    private static Configuration configuration = new Configuration();
    private static org.hibernate.SessionFactory sessionFactory;
    private static String configFile = CONFIG_FILE_LOCATION;

    static {
        try {
            configuration.configure(configFile);
            sessionFactory = configuration.buildSessionFactory();
        } catch (Exception e) {
            System.err.println("%%%% Error Creating SessionFactory %%%%");
            e.printStackTrace();
        }
    }

    private HibernateSessionFactory() {
    }

    /**
    * Returns the ThreadLocal Session instance.  Lazy initialize
    * the <code>SessionFactory</code> if needed.
    *
    *  @return Session
    *  @throws HibernateException
    */
    public static Session getSession() throws HibernateException {
        Session session = (Session) threadLocal.get();

        if ((session == null) || !session.isOpen()) {
            if (sessionFactory == null) {
                rebuildSessionFactory();
            }

            session = (sessionFactory != null) ? sessionFactory.openSession()
                                               : null;
            threadLocal.set(session);
        }

        return session;
    }

    /**
    *  Rebuild hibernate session factory
    *
    */
    public static void rebuildSessionFactory() {
        try {
            configuration.configure(configFile);
            sessionFactory = configuration.buildSessionFactory();
        } catch (Exception e) {
            System.err.println("%%%% Error Creating SessionFactory %%%%");
            e.printStackTrace();
        }
    }

    /**
    *  Close the single hibernate session instance.
    *
    *  @throws HibernateException
    */
    public static void closeSession() throws HibernateException {
        Session session = (Session) threadLocal.get();
        threadLocal.set(null);

        if (session != null) {
            session.close();
        }
    }

    /**
    *  return session factory
    *
    */
    public static org.hibernate.SessionFactory getSessionFactory() {
        return sessionFactory;
    }

    /**
    *  return session factory
    *
    *        session factory will be rebuilded in the next call
    */
    public static void setConfigFile(String configFile) {
        HibernateSessionFactory.configFile = configFile;
        sessionFactory = null;
    }

    /**
    *  return hibernate configuration
    *
    */
    public static Configuration getConfiguration() {
        return configuration;
    }

    /**
    *  Rollback hibernate Transaction
    *
    */
    public static void rollback() {
        if ((getSession().getTransaction() != null) &&
                (getSession().getTransaction().isActive() == true)) {
            getSession().getTransaction().rollback();
        }
    }

    /**
     *  Begin hibernate Transaction
     *
     */
    public static void beginTransaction() {
        getSession().getTransaction().begin();
    }

    /**
     *  Commit hibernate Transaction
     *
     */
    public static void commit() {
        getSession().getTransaction().commit();
    }

    /**
     *  Create hibernate Query
     *
     */
    public static Query createQuery(String query) {
        return getSession().createQuery(query);
    }

    /**
     *  Flush hibernate Session
     *
     */
    public static void flush() {
        getSession().flush();
    }
}
